Aqueos extract from Hibiscus sabdariffae flos and ethanolic (50°) extract from Calendulae flos were obtained, analysed and incorporated in oil/water emulsions in order to determine the antioxidant activity which makes them possible preservatives. The constituents of interest (anthocyanins, flavonoids, polyphenolcarboxylic acids, carotenoids) have been identified and dosed successfully using spectrophotometric methods, ensuring about the quality of extracts. Simple emulsion with 10% sunflower oil was chosen to evaluate the antioxidant activity in emulsions, comparing them with references in concentrations between 0.25% and 5% (ascorbic acid, ascorbyl palmitate, tocopherol and rosemary extract). Both assays applied (ferric reducing power and organoleptic examination) have revealed the ability of the proposed extracts to improve emulsions preservation.